Moulds in the Workplace

Moulds are common forms of fungi and can be found widely in the natural environment - both indoors and outdoors. They tend to grow where there is a food source (wood, paper, carpet etc.), oxygen and moisture (such as high humidity, damp or water damage). Moulds reproduce by producing spores which can become airborne and cause mould to spread. The main means of exposure to moulds is via inhalation but exposure can also occur via ingestion or contact with mouldy surfaces.

Health Effects of Moulds

Most moulds are harmless and in many cases are beneficial, being used for the production of antibiotics such as penicillin and foods such as cheese. The majority of people experience no ill effects from exposure to moulds. However, some people may be more sensitive to moulds, especially those with underlying health issues.

Some moulds can produce allergenic, toxigenic or pathogenic effects. 

• Allergenic moulds: These moulds do not produce life threatening health effects and are most likely to affect those who are already allergenic or asthmatic e.g. Alternaria, Aspergillus, Cladosporium and Penicillium spp.
• Pathogenic moulds: These moulds produce an infection and may be a problem for people with suppressed immune systems.
• Toxigenic moulds: Some moulds can produce toxic agents known as mycotoxins e.g. Aspergillus species, Fusarium species. These can produce adverse health effects e.g. some moulds may cause cancer.

Visible mould on surfaces may be an indication of more serious contamination underneath.

Controlling Indoor Mould Growth

Indoor mould growth can be prevented and controlled by:

• good building design;
• good housekeeping; and
• maintenance of a clean and dry environment - moisture control is essential in mould control. For example, any leaks should be repaired.

Further Information

• Guidance for Managing Growth in State Buildings (State Claims Agency)
• Guidance for Maintenance Staff on Managing Mould Growth in State Buildings (State Claims Agency)
• Guidance for Cleaning Staff on Managing Growth in State Buildings (State Claims Agency)
• National Guidelines for the Prevention of Nosocomial Aspergillosis (Health Protection Surveillance Centre)
• Preventing Aspergillus Infection During Hospital Construction Work (Health Protection Surveillance Centre)